It’s said, ETL concept gained popularity in the 1970s when organizations began using multiple data repositories, or databases, to store different types of business information but only as a technical concept. The need to integrate data that was spread across these databases grew quickly. ETL became the standard method for taking data from disparate sources and transforming it before loading it to a target source, or destination. In the late 1980s and early 1990s, data warehouses came onto the scene. A distinct type of database, data warehouses provided integrated access to data from multiple systems – mainframe computers, minicomputers, personal computers and spreadsheets. Coupled with mergers and acquisitions, many organizations wound up with several different ETL solutions that were not integrated.